GOA Flathead sole sensitivity runs 2022
This document contains the sensitivity runs mentioned in the “responses to SSC…” and “data gaps and future research” sections of the 2022 SAFE. Because they are not presented as alternative models, we elected to provide these as online, supplementary material. Qualitative descriptions of these explorations are retained in the SAFE text.
Sensitivity Runs indicated by SSC/CIE comments
Truncate survey data before 1993
Begin recruitment deviations in 1983
Analytical or estimated survey catchability (q)
Both models where q was allowed to estimate/calculate ended up with values around 1.65.
Additional Sensitivity runs
Unweighted Model
This model has no data weights on any source, so the input sample sizes for the compositional data are taken as-is.
Francis weights instead of McCallister-Ianelli
The Francis weights are much lower overall than those suggested by M-I.
Name Type New_MI New_Francis
1 Fishery len 1.400244 0.188829
2 Survey len 1.132556 0.571484
3 Survey age 0.312384 0.225432
Previous ageing error matrix
Outputs from this approach can be found at the bottom of this page.
Estimate steepness
H was allowed to be estimated and landed right at 0.99, so the resultant outputs are indistinguishable from the original model (with it fixed). It’s hard to say at this point whether we have or do not have evidence for density dependence, particularly because this species is so lightly exploited. For now I am OK with leaving the steepness as-is.
[1] "SR_BH_steep" "SR_LN(R0)"